diff --git a/.golangci.yml b/.golangci.yml
index 524fc7f8..6c81c4a9 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -1,6 +1,5 @@
 run:
   concurrency: 4
-  deadline: 5m
   issues-exit-code: 1
   tests: true
 
@@ -13,15 +12,13 @@ linters-settings:
 linters:
   enable:
     - govet
-    - deadcode
     - errcheck
     - govet
     - ineffassign
     - staticcheck
-    - structcheck
     - typecheck
     - unused
-    - varcheck
+    - spancheck
     - bodyclose
     - gci
     - goconst
@@ -41,4 +38,5 @@ linters:
     - prealloc
     - unconvert
     - unparam
+    - unused
   disable-all: false
diff --git a/broker/options.go b/broker/options.go
index baa72ee9..ddc12e32 100644
--- a/broker/options.go
+++ b/broker/options.go
@@ -58,14 +58,14 @@ func NewOptions(opts ...options.Option) Options {
 type PublishOptions struct {
 	// Context holds external options
 	Context context.Context
-	// BodyOnly flag says the message contains raw body bytes
-	BodyOnly bool
 	// Message metadata usually passed as message headers
 	Metadata metadata.Metadata
 	// Content-Type of message for marshal
 	ContentType string
 	// Topic destination
 	Topic string
+	// BodyOnly flag says the message contains raw body bytes
+	BodyOnly bool
 }
 
 // NewPublishOptions creates PublishOptions struct
diff --git a/broker/subscriber.go b/broker/subscriber.go
index c330c022..e30c6cce 100644
--- a/broker/subscriber.go
+++ b/broker/subscriber.go
@@ -19,8 +19,8 @@ var typeOfError = reflect.TypeOf((*error)(nil)).Elem()
 
 // Is this an exported - upper case - name?
 func isExported(name string) bool {
-	rune, _ := utf8.DecodeRuneInString(name)
-	return unicode.IsUpper(rune)
+	r, _ := utf8.DecodeRuneInString(name)
+	return unicode.IsUpper(r)
 }
 
 // Is this type exported or a builtin?
diff --git a/database/dsn.go b/database/dsn.go
index 8e6627a8..d4b158fc 100644
--- a/database/dsn.go
+++ b/database/dsn.go
@@ -75,78 +75,80 @@ func ParseDSN(dsn string) (*Config, error) {
 	// Find last '/' that goes before dbname
 	foundSlash := false
 	for i := len(dsn) - 1; i >= 0; i-- {
-		if dsn[i] == '/' {
-			foundSlash = true
-			var j, k int
+		if dsn[i] != '/' {
+			continue
+		}
 
-			// left part is empty if i <= 0
-			if i > 0 {
-				// Find the first ':' in dsn
-				for j = i; j >= 0; j-- {
-					if dsn[j] == ':' {
-						cfg.Scheme = dsn[0:j]
-					}
+		foundSlash = true
+		var j, k int
+
+		// left part is empty if i <= 0
+		if i > 0 {
+			// Find the first ':' in dsn
+			for j = i; j >= 0; j-- {
+				if dsn[j] == ':' {
+					cfg.Scheme = dsn[0:j]
 				}
-
-				// [username[:password]@][host]
-				// Find the last '@' in dsn[:i]
-				for j = i; j >= 0; j-- {
-					if dsn[j] == '@' {
-						// username[:password]
-						// Find the second ':' in dsn[:j]
-						for k = 0; k < j; k++ {
-							if dsn[k] == ':' {
-								if cfg.Scheme == dsn[:k] {
-									continue
-								}
-								var err error
-								cfg.Password, err = url.PathUnescape(dsn[k+1 : j])
-								if err != nil {
-									return nil, err
-								}
-								break
-							}
-						}
-						cfg.Username = dsn[len(cfg.Scheme)+3 : k]
-						break
-					}
-				}
-
-				for k = j + 1; k < i; k++ {
-					if dsn[k] == ':' {
-						cfg.Host = dsn[j+1 : k]
-						cfg.Port = dsn[k+1 : i]
-						break
-					}
-				}
-
 			}
 
-			// dbname[?param1=value1&...&paramN=valueN]
-			// Find the first '?' in dsn[i+1:]
-			for j = i + 1; j < len(dsn); j++ {
-				if dsn[j] == '?' {
-					parts := strings.Split(dsn[j+1:], "&")
-					cfg.Params = make([]string, 0, len(parts)*2)
-					for _, p := range parts {
-						k, v, found := strings.Cut(p, "=")
-						if !found {
-							continue
+			// [username[:password]@][host]
+			// Find the last '@' in dsn[:i]
+			for j = i; j >= 0; j-- {
+				if dsn[j] == '@' {
+					// username[:password]
+					// Find the second ':' in dsn[:j]
+					for k = 0; k < j; k++ {
+						if dsn[k] == ':' {
+							if cfg.Scheme == dsn[:k] {
+								continue
+							}
+							var err error
+							cfg.Password, err = url.PathUnescape(dsn[k+1 : j])
+							if err != nil {
+								return nil, err
+							}
+							break
 						}
-						cfg.Params = append(cfg.Params, k, v)
 					}
-
+					cfg.Username = dsn[len(cfg.Scheme)+3 : k]
 					break
 				}
 			}
-			var err error
-			dbname := dsn[i+1 : j]
-			if cfg.Database, err = url.PathUnescape(dbname); err != nil {
-				return nil, fmt.Errorf("invalid dbname %q: %w", dbname, err)
+
+			for k = j + 1; k < i; k++ {
+				if dsn[k] == ':' {
+					cfg.Host = dsn[j+1 : k]
+					cfg.Port = dsn[k+1 : i]
+					break
+				}
 			}
 
-			break
 		}
+
+		// dbname[?param1=value1&...&paramN=valueN]
+		// Find the first '?' in dsn[i+1:]
+		for j = i + 1; j < len(dsn); j++ {
+			if dsn[j] == '?' {
+				parts := strings.Split(dsn[j+1:], "&")
+				cfg.Params = make([]string, 0, len(parts)*2)
+				for _, p := range parts {
+					k, v, found := strings.Cut(p, "=")
+					if !found {
+						continue
+					}
+					cfg.Params = append(cfg.Params, k, v)
+				}
+
+				break
+			}
+		}
+		var err error
+		dbname := dsn[i+1 : j]
+		if cfg.Database, err = url.PathUnescape(dbname); err != nil {
+			return nil, fmt.Errorf("invalid dbname %q: %w", dbname, err)
+		}
+
+		break
 	}
 
 	if !foundSlash && len(dsn) > 0 {
diff --git a/go.mod b/go.mod
index 80403212..5a3afc27 100644
--- a/go.mod
+++ b/go.mod
@@ -5,17 +5,16 @@ go 1.20
 require (
 	dario.cat/mergo v1.0.0
 	github.com/DATA-DOG/go-sqlmock v1.5.0
-	github.com/google/uuid v1.3.1
+	github.com/google/uuid v1.6.0
 	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/silas/dag v0.0.0-20220518035006-a7e85ada93c5
-	golang.org/x/sync v0.3.0
-	golang.org/x/sys v0.12.0
-	google.golang.org/grpc v1.58.2
-	google.golang.org/protobuf v1.31.0
+	golang.org/x/sync v0.6.0
+	golang.org/x/sys v0.16.0
+	google.golang.org/grpc v1.62.1
+	google.golang.org/protobuf v1.32.0
 )
 
 require (
 	github.com/golang/protobuf v1.5.3 // indirect
-	golang.org/x/net v0.15.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20230711160842-782d3b101e98 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80 // indirect
 )
diff --git a/go.sum b/go.sum
index 1bc873a5..cef2316a 100644
--- a/go.sum
+++ b/go.sum
@@ -6,29 +6,28 @@ github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaS
 github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
 github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
-github.com/google/uuid v1.3.1 h1:KjJaJ9iWZ3jOFZIf1Lqf4laDRCasjl0BCmnEGxkdLb4=
-github.com/google/uuid v1.3.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
 github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/silas/dag v0.0.0-20220518035006-a7e85ada93c5 h1:G/FZtUu7a6NTWl3KUHMV9jkLAh/Rvtf03NWMHaEDl+E=
 github.com/silas/dag v0.0.0-20220518035006-a7e85ada93c5/go.mod h1:7RTUFBdIRC9nZ7/3RyRNH1bdqIShrDejd1YbLwgPS+I=
-golang.org/x/net v0.15.0 h1:ugBLEUaxABaB5AJqW9enI0ACdci2RUd4eP51NTBvuJ8=
-golang.org/x/net v0.15.0/go.mod h1:idbUs1IY1+zTqbi8yxTbhexhEEk5ur9LInksu6HrEpk=
-golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
-golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
-golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
-golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
+golang.org/x/net v0.20.0 h1:aCL9BSgETF1k+blQaYUBx9hJ9LOGP3gAVemcZlf1Kpo=
+golang.org/x/sync v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=
+golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
+golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20230711160842-782d3b101e98 h1:bVf09lpb+OJbByTj913DRJioFFAjf/ZGxEz7MajTp2U=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20230711160842-782d3b101e98/go.mod h1:TUfxEVdsvPg18p6AslUXFoLdpED4oBnGwyqk3dV1XzM=
-google.golang.org/grpc v1.58.2 h1:SXUpjxeVF3FKrTYQI4f4KvbGD5u2xccdYdurwowix5I=
-google.golang.org/grpc v1.58.2/go.mod h1:tgX3ZQDlNJGU96V6yHh1T/JeoBQ2TXdr43YbYSsCJk0=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80 h1:AjyfHzEPEFp/NpvfN5g+KDla3EMojjhRVZc1i7cj+oM=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80/go.mod h1:PAREbraiVEVGVdTZsVWjSbbTtSyGbAgIIvni8a8CD5s=
+google.golang.org/grpc v1.62.1 h1:B4n+nfKzOICUXMgyrNd19h/I9oH0L1pizfk1d4zSgTk=
+google.golang.org/grpc v1.62.1/go.mod h1:IWTG0VlJLCh1SkC58F7np9ka9mx/WNkjl4PGJaiq+QE=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
-google.golang.org/protobuf v1.31.0 h1:g0LDEJHgrBl9N9r17Ru3sqWhkIx2NB67okBHPwC7hs8=
-google.golang.org/protobuf v1.31.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
+google.golang.org/protobuf v1.32.0 h1:pPC6BG5ex8PDFnkbrGU3EixyhKcQ2aDuBS36lqK/C7I=
+google.golang.org/protobuf v1.32.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/logger/options.go b/logger/options.go
index 4424c612..8755c9b7 100644
--- a/logger/options.go
+++ b/logger/options.go
@@ -18,18 +18,12 @@ type Options struct {
 	Out io.Writer
 	// Context holds exernal options
 	Context context.Context
-	// Attrs holds additional attributes
-	Attrs []interface{}
-	// Name holds the logger name
-	Name string
-	// The logging level the logger should log
-	Level Level
-	// CallerSkipCount number of frmaes to skip
-	CallerSkipCount int
-	// ContextAttrFuncs contains funcs that executed before log func on context
-	ContextAttrFuncs []ContextAttrFunc
+	// TimeFunc used to obtain current time
+	TimeFunc func() time.Time
 	// TimeKey is the key used for the time of the log call
 	TimeKey string
+	// Name holds the logger name
+	Name string
 	// LevelKey is the key used for the level of the log call
 	LevelKey string
 	// MessageKey is the key used for the message of the log call
@@ -40,12 +34,18 @@ type Options struct {
 	SourceKey string
 	// StacktraceKey is the key used for the stacktrace
 	StacktraceKey string
+	// Attrs holds additional attributes
+	Attrs []interface{}
+	// ContextAttrFuncs contains funcs that executed before log func on context
+	ContextAttrFuncs []ContextAttrFunc
+	// CallerSkipCount number of frmaes to skip
+	CallerSkipCount int
+	// The logging level the logger should log
+	Level Level
 	// AddStacktrace controls writing of stacktaces on error
 	AddStacktrace bool
 	// AddSource enabled writing source file and position in log
 	AddSource bool
-	// TimeFunc used to obtain current time
-	TimeFunc func() time.Time
 }
 
 // NewOptions creates new options struct
diff --git a/logger/unwrap/unwrap.go b/logger/unwrap/unwrap.go
index e13844fb..3c456f19 100644
--- a/logger/unwrap/unwrap.go
+++ b/logger/unwrap/unwrap.go
@@ -56,9 +56,9 @@ type Wrapper struct {
 	s                fmt.State
 	pointers         map[uintptr]int
 	opts             *Options
+	takeMap          map[int]bool
 	depth            int
 	ignoreNextType   bool
-	takeMap          map[int]bool
 	protoWrapperType bool
 	sqlWrapperType   bool
 }
diff --git a/metadata/metadata_test.go b/metadata/metadata_test.go
index 6155e535..809f5274 100644
--- a/metadata/metadata_test.go
+++ b/metadata/metadata_test.go
@@ -54,7 +54,24 @@ func testOutgoingCtx(ctx context.Context) {
 	}
 }
 
-func TestPassing(t *testing.T) {
+func TestIncoming(t *testing.T) {
+	ctx := context.TODO()
+	md1 := New(2)
+	md1.Set("Key1", "Val1")
+	md1.Set("Key2", "Val2")
+
+	ctx = NewIncomingContext(ctx, md1)
+	testIncomingCtx(ctx)
+	md, ok := FromIncomingContext(ctx)
+	if !ok {
+		t.Fatalf("missing metadata from incoming context")
+	}
+	if v, ok := md.Get("Key1"); !ok || v != "Val1_new" {
+		t.Fatalf("invalid metadata value %#+v", md)
+	}
+}
+
+func TestOutgoing(t *testing.T) {
 	ctx := context.TODO()
 	md1 := New(2)
 	md1.Set("Key1", "Val1")
diff --git a/micro.go b/micro.go
index c86955c8..6163b2e1 100644
--- a/micro.go
+++ b/micro.go
@@ -65,6 +65,8 @@ func As(b any, target any) bool {
 			break
 		case targetType.Implements(routerType):
 			break
+		case targetType.Implements(tracerType):
+			break
 		default:
 			return false
 		}
@@ -76,19 +78,21 @@ func As(b any, target any) bool {
 	return false
 }
 
-var brokerType = reflect.TypeOf((*broker.Broker)(nil)).Elem()
-var loggerType = reflect.TypeOf((*logger.Logger)(nil)).Elem()
-var clientType = reflect.TypeOf((*client.Client)(nil)).Elem()
-var serverType = reflect.TypeOf((*server.Server)(nil)).Elem()
-var codecType = reflect.TypeOf((*codec.Codec)(nil)).Elem()
-var flowType = reflect.TypeOf((*flow.Flow)(nil)).Elem()
-var fsmType = reflect.TypeOf((*fsm.FSM)(nil)).Elem()
-var meterType = reflect.TypeOf((*meter.Meter)(nil)).Elem()
-var registerType = reflect.TypeOf((*register.Register)(nil)).Elem()
-var resolverType = reflect.TypeOf((*resolver.Resolver)(nil)).Elem()
-var routerType = reflect.TypeOf((*router.Router)(nil)).Elem()
-var selectorType = reflect.TypeOf((*selector.Selector)(nil)).Elem()
-var storeType = reflect.TypeOf((*store.Store)(nil)).Elem()
-var syncType = reflect.TypeOf((*sync.Sync)(nil)).Elem()
-var tracerType = reflect.TypeOf((*tracer.Tracer)(nil)).Elem()
-var serviceType = reflect.TypeOf((*Service)(nil)).Elem()
+var (
+	brokerType   = reflect.TypeOf((*broker.Broker)(nil)).Elem()
+	loggerType   = reflect.TypeOf((*logger.Logger)(nil)).Elem()
+	clientType   = reflect.TypeOf((*client.Client)(nil)).Elem()
+	serverType   = reflect.TypeOf((*server.Server)(nil)).Elem()
+	codecType    = reflect.TypeOf((*codec.Codec)(nil)).Elem()
+	flowType     = reflect.TypeOf((*flow.Flow)(nil)).Elem()
+	fsmType      = reflect.TypeOf((*fsm.FSM)(nil)).Elem()
+	meterType    = reflect.TypeOf((*meter.Meter)(nil)).Elem()
+	registerType = reflect.TypeOf((*register.Register)(nil)).Elem()
+	resolverType = reflect.TypeOf((*resolver.Resolver)(nil)).Elem()
+	routerType   = reflect.TypeOf((*router.Router)(nil)).Elem()
+	selectorType = reflect.TypeOf((*selector.Selector)(nil)).Elem()
+	storeType    = reflect.TypeOf((*store.Store)(nil)).Elem()
+	syncType     = reflect.TypeOf((*sync.Sync)(nil)).Elem()
+	tracerType   = reflect.TypeOf((*tracer.Tracer)(nil)).Elem()
+	serviceType  = reflect.TypeOf((*Service)(nil)).Elem()
+)
diff --git a/options/options_test.go b/options/options_test.go
index acb64651..9a8946a2 100644
--- a/options/options_test.go
+++ b/options/options_test.go
@@ -1,7 +1,6 @@
 package options_test
 
 import (
-	"fmt"
 	"testing"
 
 	"go.unistack.org/micro/v4/codec"
@@ -132,7 +131,6 @@ func TestMetadataAny(t *testing.T) {
 			var opts []options.Option
 			switch valData := tt.Data.(type) {
 			case []any:
-				fmt.Printf("%s any %#+v\n", tt.Name, valData)
 				opts = append(opts, options.Metadata(valData...))
 			case map[string]string, map[string][]string, metadata.Metadata:
 				opts = append(opts, options.Metadata(valData))
diff --git a/register/memory/memory.go b/register/memory/memory.go
index e4385597..35a12562 100644
--- a/register/memory/memory.go
+++ b/register/memory/memory.go
@@ -32,10 +32,10 @@ type record struct {
 }
 
 type memory struct {
-	sync.RWMutex
 	records  map[string]services
 	watchers map[string]*watcher
 	opts     register.Options
+	sync.RWMutex
 }
 
 // services is a KV map with service name as the key and a map of records as the value
@@ -102,10 +102,20 @@ func (m *memory) sendEvent(r *register.Result) {
 }
 
 func (m *memory) Connect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
 	return nil
 }
 
 func (m *memory) Disconnect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
 	return nil
 }
 
@@ -126,6 +136,11 @@ func (m *memory) Options() register.Options {
 }
 
 func (m *memory) Register(ctx context.Context, s *register.Service, opts ...register.RegisterOption) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
 	m.Lock()
 	defer m.Unlock()
 
@@ -467,9 +482,7 @@ func serviceToRecord(s *register.Service, ttl time.Duration) *record {
 	}
 
 	endpoints := make([]*register.Endpoint, len(s.Endpoints))
-	for i, e := range s.Endpoints { // TODO: vtolstov use copy
-		endpoints[i] = e
-	}
+	copy(endpoints, s.Endpoints)
 
 	return &record{
 		Name:      s.Name,
diff --git a/register/memory/memory_test.go b/register/memory/memory_test.go
index c4dd7151..c60b9adf 100644
--- a/register/memory/memory_test.go
+++ b/register/memory/memory_test.go
@@ -3,12 +3,13 @@ package memory
 import (
 	"context"
 	"fmt"
-	"go.unistack.org/micro/v4"
-	"go.unistack.org/micro/v4/register"
 	"reflect"
 	"sync"
 	"testing"
 	"time"
+
+	"go.unistack.org/micro/v4"
+	"go.unistack.org/micro/v4/register"
 )
 
 var testData = map[string][]*register.Service{
@@ -209,9 +210,9 @@ func TestMemoryRegistryTTLConcurrent(t *testing.T) {
 		}
 	}
 
-	//if len(os.Getenv("IN_TRAVIS_CI")) == 0 {
+	// if len(os.Getenv("IN_TRAVIS_CI")) == 0 {
 	//	t.Logf("test will wait %v, then check TTL timeouts", waitTime)
-	//}
+	// }
 
 	errChan := make(chan error, concurrency)
 	syncChan := make(chan struct{})
@@ -252,6 +253,13 @@ func TestMemoryWildcard(t *testing.T) {
 	m := NewRegister()
 	ctx := context.TODO()
 
+	if err := m.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := m.Connect(ctx); err != nil {
+		t.Fatal(err)
+	}
 	testSrv := &register.Service{Name: "foo", Version: "1.0.0"}
 
 	if err := m.Register(ctx, testSrv, register.RegisterDomain("one")); err != nil {
@@ -291,8 +299,12 @@ func TestWatcher(t *testing.T) {
 
 	ctx := context.TODO()
 	m := NewRegister()
-	m.Init()
-	m.Connect(ctx)
+	if err := m.Init(); err != nil {
+		t.Fatal(err)
+	}
+	if err := m.Connect(ctx); err != nil {
+		t.Fatal(err)
+	}
 	wc, err := m.Watch(ctx)
 	if err != nil {
 		t.Fatalf("cant watch: %v", err)
diff --git a/sync/waitgroup.go b/sync/waitgroup.go
new file mode 100644
index 00000000..3124d948
--- /dev/null
+++ b/sync/waitgroup.go
@@ -0,0 +1,69 @@
+package sync
+
+import (
+	"context"
+	"sync"
+)
+
+type WaitGroup struct {
+	wg *sync.WaitGroup
+	c  int
+	mu sync.Mutex
+}
+
+func WrapWaitGroup(wg *sync.WaitGroup) *WaitGroup {
+	g := &WaitGroup{
+		wg: wg,
+	}
+	return g
+}
+
+func NewWaitGroup() *WaitGroup {
+	var wg sync.WaitGroup
+	return WrapWaitGroup(&wg)
+}
+
+func (g *WaitGroup) Add(n int) {
+	g.mu.Lock()
+	g.c += n
+	g.wg.Add(n)
+	g.mu.Unlock()
+}
+
+func (g *WaitGroup) Done() {
+	g.mu.Lock()
+	g.c += -1
+	g.wg.Add(-1)
+	g.mu.Unlock()
+}
+
+func (g *WaitGroup) Wait() {
+	g.wg.Wait()
+}
+
+func (g *WaitGroup) WaitContext(ctx context.Context) {
+	done := make(chan struct{})
+	go func() {
+		g.wg.Wait()
+		close(done)
+	}()
+
+	select {
+	case <-ctx.Done():
+		g.mu.Lock()
+		g.wg.Add(-g.c)
+		<-done
+		g.wg.Add(g.c)
+		g.mu.Unlock()
+		return
+	case <-done:
+		return
+	}
+}
+
+func (g *WaitGroup) Waiters() int {
+	g.mu.Lock()
+	c := g.c
+	g.mu.Unlock()
+	return c
+}
diff --git a/sync/waitgroup_test.go b/sync/waitgroup_test.go
new file mode 100644
index 00000000..c3f6f1b7
--- /dev/null
+++ b/sync/waitgroup_test.go
@@ -0,0 +1,37 @@
+package sync
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+func TestWaitGroupContext(t *testing.T) {
+	wg := NewWaitGroup()
+	_ = t
+	wg.Add(1)
+	ctx, cancel := context.WithTimeout(context.TODO(), 1*time.Second)
+	defer cancel()
+	wg.WaitContext(ctx)
+}
+
+func TestWaitGroupReuse(t *testing.T) {
+	wg := NewWaitGroup()
+	defer func() {
+		if wg.Waiters() != 0 {
+			t.Fatal("lost goroutines")
+		}
+	}()
+
+	wg.Add(1)
+	defer wg.Done()
+	ctx, cancel := context.WithTimeout(context.TODO(), 1*time.Second)
+	defer cancel()
+	wg.WaitContext(ctx)
+
+	wg.Add(1)
+	defer wg.Done()
+	ctx, cancel = context.WithTimeout(context.TODO(), 1*time.Second)
+	defer cancel()
+	wg.WaitContext(ctx)
+}
diff --git a/util/register/util.go b/util/register/util.go
index c235920b..a73e7f19 100644
--- a/util/register/util.go
+++ b/util/register/util.go
@@ -109,12 +109,11 @@ func Merge(olist []*register.Service, nlist []*register.Service) []*register.Ser
 				seen = true
 				srv = append(srv, sp)
 				break
-			} else {
-				sp := &register.Service{}
-				// make copy
-				*sp = *o
-				srv = append(srv, sp)
 			}
+			sp := &register.Service{}
+			// make copy
+			*sp = *o
+			srv = append(srv, sp)
 		}
 		if !seen {
 			srv = append(srv, Copy([]*register.Service{n})...)
diff --git a/util/structfs/metadata_ec2.go b/util/structfs/metadata_ec2.go
index 6c0f63aa..07be6e42 100644
--- a/util/structfs/metadata_ec2.go
+++ b/util/structfs/metadata_ec2.go
@@ -12,7 +12,7 @@ type EC2Metadata struct {
 			InstanceType       string   `json:"instance-type"`
 			LocalHostname      string   `json:"local-hostname"`
 			LocalIPv4          string   `json:"local-ipv4"`
-			kernelID           int      `json:"kernel-id"`
+			KernelID           int      `json:"kernel-id"`
 			Placement          string   `json:"placement"`
 			AvailabilityZone   string   `json:"availability-zone"`
 			ProductCodes       string   `json:"product-codes"`
diff --git a/util/structfs/structfs.go b/util/structfs/structfs.go
index 755c691c..740b3014 100644
--- a/util/structfs/structfs.go
+++ b/util/structfs/structfs.go
@@ -67,9 +67,9 @@ func (fi *fileInfo) Name() string {
 
 func (fi *fileInfo) Mode() os.FileMode {
 	if strings.HasSuffix(fi.name, "/") {
-		return os.FileMode(0755) | os.ModeDir
+		return os.FileMode(0o755) | os.ModeDir
 	}
-	return os.FileMode(0644)
+	return os.FileMode(0o644)
 }
 
 func (fi *fileInfo) IsDir() bool {
@@ -112,15 +112,14 @@ func (f *file) Readdir(count int) ([]os.FileInfo, error) {
 func (f *file) Seek(offset int64, whence int) (int64, error) {
 	//	log.Printf("seek %d %d %s\n", offset, whence, f.name)
 	switch whence {
-	case os.SEEK_SET:
+	case io.SeekStart:
 		f.offset = offset
-	case os.SEEK_CUR:
+	case io.SeekCurrent:
 		f.offset += offset
-	case os.SEEK_END:
+	case io.SeekEnd:
 		f.offset = int64(len(f.data)) + offset
 	}
 	return f.offset, nil
-
 }
 
 func (f *file) Stat() (os.FileInfo, error) {
diff --git a/util/structfs/structfs_test.go b/util/structfs/structfs_test.go
index 7abf8edb..5c198fda 100644
--- a/util/structfs/structfs_test.go
+++ b/util/structfs/structfs_test.go
@@ -2,7 +2,7 @@ package structfs
 
 import (
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"reflect"
 	"testing"
@@ -82,7 +82,7 @@ func get(path string) ([]byte, error) {
 		return nil, err
 	}
 	defer res.Body.Close()
-	return ioutil.ReadAll(res.Body)
+	return io.ReadAll(res.Body)
 }
 
 func TestAll(t *testing.T) {